The primary goal of this U01 proposal is to refine, evaluate, and disseminate a new low-cost and sustainable stepped care program for Obstetrics/Gynecology (Ob/Gyn) clinics that will improve perinatal women's treatment rates and outcomes. There is a tremendous public health need for this research as depression is the leading cause of disability among women of reproductive age worldwide. Upwards of 1 in 5 women suffer from perinatal depression. It has deleterious effects on birth outcomes, infant attachment, and children's behavior/development. Maternal suicide causes 20% of postpartum deaths in depressed women. Although the vast majority of perinatal women are amenable to being screened for depression, screening alone does not improve treatment rates or patient outcomes. Ob/Gyn clinics need supports in place to adequately address depression in their patient populations. Thus, we developed and pilot tested the Rapid Access to Perinatal Psychiatric Care in Depression (RAPPID) Program, to create a comprehensive intervention that is proactive, multifaceted, and practical. RAPPID aims to improve perinatal depression treatment and treatment response rates through: (1) access to immediate resource provision/referrals and psychiatric telephone consultation for Ob/Gyn providers; (2) clinic-specific implementation of stepped care, including training support and toolkits; and, (3) proactive treatment engagement, patient monitoring, and stepped treatment response to depression screening/assessment. RAPPID builds on a low-cost and widely disseminated population-based model for delivering psychiatric care in primary care settings developed by our team. Formative data and feedback from key stakeholders also informed the development of RAPPID. Our pilot work in real-world settings suggests RAPPID is feasible and improves depression detection and treatment in Ob/Gyn settings. Because it uses existing infrastructure and resources, RAPPID, has the potential to be feasible, sustainable and transportable to other practice settings. We propose to compare two active interventions, RAPPID vs. enhanced usual care (access to resource provision/referrals and psychiatric telephone consultation) in a cluster-randomized trial in which we will randomize 12 Ob/Gyn clinics to either RAPPID or enhanced usual care. We will compare the effectiveness of RAPPID vs. enhanced usual care to improve depression severity and treatment participation in pregnancy through 12 months postpartum among 300 patients (n=150/group, 25/clinic). We will then disseminate findings and recommendations via a multi-dimensional dissemination strategy to facilitate national uptake. Our established relationships with stakeholders boosts the potential for widespread dissemination and implementation of RAPPID. Our combined expertise in the integration of obstetric and depression care, cluster-randomized trials and Ob/Gyn make us ideally suited to implement, test and widely disseminate RAPPID. If proven effective, RAPPID will be poised for national dissemination.